A 70-year-old male patient with intentional tremor, drunken gait, and past pointing is having a lesion in which of the following structures

"Most abnormalities associated with damage to the cerebellum are apparent during movement Ataxia is manifest not only in the wide-based, unsteady, "drunken" gait of patients but also in defects of the skilled movements involved in the production of speech, so that slurred, scanning speech results. Voluntary movements are also highly abnormal when the cerebellum is damaged. For example, attempting to touch an object with a finger results in overshooting. This dysmetria or past-pointing promptly initiates a gross corrective action, but the correction overshoots to the other side, and the finger oscillates back and foh. This oscillation is called an intention tremor."